Prepare a macaron template by using a large piping tip or small round cookie cutter of about 1 ½″ in size to trace circles about 2 inches apart on one sheet of parchment paper. You will place this under another piece of parchment paper when ready to pipe the macaron shells.

In a medium bowl, sift the almond flour and powdered sugar twice. Set aside.

In a small heat-proof bowl, whisk together the egg whites and granulated sugar. Place the bowl over a small saucepan of simmering water, and whisk often until the sugar has dissolved or until the temperature is about 120 degrees F.

Transfer the egg white mixture to the bowl of a stand mixer fitted with a whisk attachment. Whisk until the mixture reaches soft peaks. At this point, you can add the vanilla and green food gel.

Continue whisking the meringue until stiff peaks form.

Start the macaronage by folding in ⅓ of the dry ingredients. Mix carefully with a rubber spatula by scraping around the sides of the bowl, then through the middle of the batter. Do this a few times until it is mostly combined.

Add the remainder of the dry ingredients, folding with the same gentle method. Once the dry ingredients are fully incorporated, begin spreading the batter along the sides of the bowl to deflate it slightly. Continue scraping around the sides of the bowl and through the middle. The mixture is ready when you can draw several figure eights without the batter breaking.

Transfer the batter to a piping bag with a small round piping tip (I used Ateco 802).

Place your macaron template under another piece of parchment paper on a baking sheet and pipe perpendicular to fill in each circle.

Carefully remove the template and tap the baking sheet on the on counter a few times in order to release any air bubbles. It also helps to bang on the bottom of the baking sheet with your hand.

Let the macarons rest for about 30-40 minutes, or until they are dry and no longer sticky to the touch.

Meanwhile, preheat the oven to 300 degrees F.

Bake the macarons for about 12-14 minutes. Allow to cool completely before peeling them off of the parchment paper.

Place the egg yolks and 12g of sugar in a medium bowl or a bowl of a stand mixer fitted with a whisk attachment. Whisk on high speed until thick and foamy (about 3 minutes) while you heat the sugar and water.

In a small saucepan, place the remaining 50g of granulated sugar and water over low heat, stirring constantly until the sugar dissolves. Increase the heat to medium and bring to a boil, or until it reaches 240 degrees F.

While the egg yolks are still whisking on medium speed, slowly drizzle the sugar syrup into the bowl. Continue mixing until the mixture has cooled down to room temperature.

Add the butter to the mixture a few cubes at a time, allowing them to fully incorporate before adding more.

Lastly, add the pistachio paste, vanilla, and green food gel. Continue mixing on low speed until the buttercream is completely smooth.

Transfer the buttercream to a piping bag fitted with a small round tip (I used Ateco 803).

Pair the macarons up and pipe the buttercream onto the bottom shell. Optionally, pipe pistachio paste into the center of each.

Place the paired shell on top, pressing down slightly to ensure they stick together.

Place in the fridge until ready to serve.